Q400 | Digital Image Correlation

Full field Deformation Measurement

Flexible strain sensor for a wide application range

Field of View of 1x1mm² to 10x10m²

Easy usage and fully automatic calibration within 20 seconds

Integrated Analysis modules for automatic post processing

Certifiable after ISO9513 (precision classes)

Q400 - measurement system for 3D deformation analysis at material tests and component tests

With the Q400 system, the 2D or 3D deformation analysis is performed in a precise, fast and user-friendly manner. The modular system is also characterized by the high flexibility of the optical setup and thus can be optimally adapted to the application. The intuitive measuring software Istra4D provides, in addition to the spatial measured values displacement, deformation, strain, coordinates, etc. also the corresponding measuring accuracy for each measured value.

Measuring principle:
One or more digital cameras record the deformation process. The object surface has a stochastic (natural or prepared) pattern ("speckle pattern"). The images are automatically evaluated using subpixel-accurate digital image correlation algorithms. This assigns the local surface pattern to the camera pixels and measures 3D coordinates, 3D displacements, 3D deformations and surface strains components.

Features

Spatial measurement of 3D coordinates, displacements and strain tensors shown as 2D overlay or 3D model
Fully automatic calibration with real-time tracking and quality feedback
'Genuine' multi-camera system - Fully integrated system with up to 8 cameras for improved accuracy and surface coverage on complex surfaces and complete detection of a cylinder.
4-camera system for simultaneous measurement of the front and rear sides as well as thickness and thickness change.
Modular software package for image acquisition, evaluation and visualization.
Powerful integration of CCD and high-speed cameras
Synchronized image recording with up to 8 analog input signals
Fully automatic calibration with real-time tracking and live quality feedback
Custom coordinate systems
The measurement accuracy (Confidence Margin) is given for each variable based on an internal error calculation. Full field error estimation for each measuring point.
Open-source data format. Direct data access from Matlab, Scilab, etc.
Open-Source Datenformat. Direkter Daten-Zugriff aus Matlab, Scilab, etc.
Programmable image acquisition - Realization of complex recording processes (trigger, frame rate, time, analog value change, phase position, ...)

Measured strain distribution on a wrench

Result of a Q400 strain measurement of a water pipe wrench. The color scale shows tensile
strain (red) and compression strain (blue) corresponding to the mechanical load of the wrench.

Technical Specifications

System type	Description	Applications
Q-400-2D	2D-DIC "Entry system" with one camera	Measurement at flat specimen
Q-400-3D	3D-DIC Stereo system	Measurement at all surface geometries
Q-400-EDU	3D-DIC system for educational institutions	Flexible system for any measurements in teaching and internships
Q-400-4CAM	3D-DIC system with 4 cameras (2x 2 cameras)	For the measurement of the strain distribution at material tests. Simultaneous measurement of the strain distribution at front and back side and thickness, thickness change and volume.
Q-400-MultiCAM	Multi camera system	Measurement up to 360° object surpface with 8 cameras
Q-400-µDIC	DIC system with stereo microscope	Measurement at small FOV (0,5 x 0,5mm to 17x17mm)
Q-400-Vibro	Combination of Q400 and trigger unit PhaseTriggerLS (Strobe-CAM)	For vibration measurement, mode shapes, fatigue tests
Q-450	Systems with high speed cameras	For dynamic applications and for vibration measurement at non periodic excitations

Characteristics (depending on the selected system hardware):

Field of View	1mm² to 100m² (with standard lenses)
Precision for 3D displacements	0.01 pixel (corrsponds to 1µm with 1Mpixel camera and 100x100mm FOV)
Precision for strain	200 µstrains (=0.02%)
Strain measurement range	1µstrain to 1000%
Camera resolution	0,3 Mpixel (VGA) to 29 Mpixel
Acquisition rate	10 images/s to 2.000.000 images/s
Real time analysis	Optional software module

Applications

The applications field of the Q400 systems is very wide spread.
The essential prerequisite for the application are

The optical access of the component surface to be measured
A natural pattern present on the surface or a prepared speckle pattern

It can be measured on nearly all materials like: wood, metals, plastics, (metal) foams, rubber, composites, paper, etc.

Typical applications:

Material testing for the determination of material parameters such as Young's modulus, Poisson number, u.v.m.
Component testing: Component tests, strength tests, stress tests, test benches, temperature chambers, tensile testing machines
Validation of FEM simulations
Crack propagation, crack growth
Delamination tests
Fracture Mechanics
Dynamic tests: crash tests, pedestrian safety, airbag tests, rapid tensile tests
Vibration measurement, vibration tests
Fatigue tests, Relaxation tests
Measurement of thermal expansion coefficients

To the list of scientific articles in which the Q400-System was used.

To the applications examples

Deformation analysis & Component testing

Material testing

Vibration analysis

Measurement principle

Pattern recognition

Digital image correlation is a camera based technique for the measurement of deformations on object surfaces. The method tracks the grey value pattern (speckle pattern") in small neighborhoods ("subsets" or "facettes") shown light blue in the camera images.

The measurement principle of digital image correlation show the deformation of the subsets

Reference state vs. deformed state

Spatially Resolved Measurement The analysis of images and sequences with digital image correlation allows the measurement of displacements and deformations at every camera pixel. The resulting fullfield information is very comprehensive and has many advantages compared to other measurement techniques. The images show the speckle pattern of an object without and with deformation and the measured strain distribution.	Undeformed state	Deformed state	Strain distribution
		Major strain E1 of the image sequence.

3D DIC

During the object deformation stereo images are recorded with two cameras. The stereo correlation between the left and right images measures the geometry and position of the object at every load stage.

The two shown images are recorded simultaneously with the left and right camera of a stereo system.

The principle of stereo correlation measures the 3D geometry of the object

3D geometry by stereo correlation

Time Course

The temporal correlation between reference state and deformed state calculates the 3D displacement and 3D deformation of the object.

Strain field measured on a aircraft wing at bending load using digital image correlation

Strain calculation by stereo correlation and temporal crrelation.

Software

Software

Functionality

Istra4D

Modular software package with integrates

Camera control
Automatic Real time calibration
Images acquisition
Analysis

Import and export of external image sources (e.g., high-speed camera, microscope)

Visualization of the spatially resolved measurement results as a 2D color overlay or as a 3D representation

Data display on points, lines, polygonal lines as well as circular and polygonal areas

Definition of "virtual strain gauge"

Definition of "virtual extensometers" with a definable length

Temporal diagram plots of variables

Spatial variable diagrams of polygonal line sections

Multiple possibilities of data export (ASCII, STL, HDF5)

Generation of AVI videos and image export of results

Integrated analysis modules (scripting):

Automatic calculation of complex measured variables
Generation of results diagrams
The scope of delivery includes a wide range of evaluation modules e.g. for the determination of material parameters
Easy adaptation of the analysis modules by the user or LIMESS